Apparatus for gravity separation of materials



c. J. FOYSTER 3,347,377

APPARATUS FOR GRAVITY SEPARATION OF MATERIALS Oct. 17, 1967 Filed Feb. 5, 1965 2 Sheets-$heet 1 Oct. 17, 1967 CQJ. FOY'STER ,3

APPARATUS FOR GRAVITY SEPARATION OF MATERIALS Filed Feb. 5,1965 2 Sheets-Sheet 2 United States Patent 3,347,377 APPARATUS FOR GRAVITY SEPARATION OF MATERIALS Clive John Foyster, Griffith St., Coolangatta,

. Queensland, Australia Filed Feb. 5, 1965, Ser. No. 430,669 Claims priority, application Australia, Feb. 6, 1964, 40,636/ 64 3 Claims. (Cl. 209-458) This invention relates to apparatus for gravity separation of materials, and particularly of mineral sands.

In the mining of mineral sands, involving the separation of the proportion of mineral sands found, in certain areas, mixed with a generally much larger proportion of silicon sands, an upgrader is used. The general purpose of an upgrader is to eliminate a large proportion of the silicon sand, yielding a concentrate very rich in mineral sands, and which may be conveniently conveyed to a plant for further concentration and separation of the various mineral sand components. It is desirable that an upgrader should eliminate 40% and more of the total sand, without unacceptable tailing losses, and it is a general object of the present invention to provide apparatus usable as an upgrader (and also usable as a tails scavenger unit), which will effectively achieve this. Another object achieved by preferred embodiments of the invention is to provide such an apparatus which is particularly compact, but which at the same time has a high through-put rate, and is thus particularly advantageous in installations where large numbers of upgraders and tails scavenger units are required to be used for rapid treatment of sands. A further object achievable by the invention is to provide such an apparatus which is readily controllable as may be from time to time required, to suit varying conditions. Other objects are to provide such apparatus which is simple and economical to manufacture and to operate and test during operations.

[in order that a preferred embodiment of the invention may be readily understood and carried into practical effect, reference is now made to the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a mineral sands separation unit according to the invention,

FIG. 2 is a plan view of the apparatus, in the direction of the arrow in FIG. 1,

FIG. 3 is a sectional view, to enlarged scale, along line 3-3 in FIG. 2, and

FIG. 4 is a detail planview of part of one of the sluice side wall adjusting devices of the apparatus.

, The apparatus shown in the drawings includes a main frame including a pair of parallel base channel members 10, on each of which there are mounted a number of perpendicular uprights 11, interconnected at their upper ends by a top member 12 and braced by stays 13. The two parallel top members 12 of the main frame are interconnected by top transverse members 14.

Between the uprights 11 at both sides of the main frame there are mounted a series of similar parallel and fairly closely spaced upgrading trays 15, each supported on transverse angle-iron members 16 secured between corresponding uprights 11.

The main frame is tilted, as shown in FIG. 1, so that all of the trays 15 incline downwardly from rear to front, at an angle of about 16 to horizontal.

Each of the trays includes a rectangular bottom 17, and perpendicular side walls 18, all of which may be of water resistant plywood.

Across the rear of each tray, there is a transverse boxlike distributor 19, open at the front. The interior of this distributor is divided into four compartments by three longitudinal division pieces 20 secured to the tray bottom,

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and extending forwardly of the distributor. In front of each division piece 20 there is secured to the tray bottom a diverter piece 21, substantially of isosceles triangular shape in plan view, and, aligned laterally with these, a narrower diverter piece 21a is secured to the right-hand side wall 18.

At regular intervals down the tray, there are secured further laterally aligned series of diverter pieces 21 and 210, corresponding diverter pieces of the several series being longitudinally aligned, as shown in FIG. 2.

With each of the diverter pieces 21 of each series there is associated a fixed sluice side wall 22, which may be a strip of water-resistant plywood which at its rear is recessed into and secured to the lower right-hand part of the diverter pieces, and is secured perpendicularly to the upgrader tray bottom 17, inclining forwardly towards the right. In alignment with and parallel to the fixed sluice side walls 22 of each series is a further fixed sluice side wall 22a, its rear being faired into and secured to the left-hand tray side wall 18.

Associated with each one of each series of diverter pieces 21, 21a, is a movable sluice side wall 23-, which may consist of a strip of water-resistant plywood with a strip 24 of neoprene or the like extending down from its bottom, the rear end of the movable sluice side wall being pivoted at 25 to the front left-hand part of the diverter piece 21 or 21w, the movable side wall, perpendicular to the tray bottom 17, inclining forwardly towards the left.

Each convergent pair of fixed sluice side walls 22 or 22a and movable sluice side walls 23, together with the associated diverter piece or pieces 21, 21a, and the portion of tray bottom 17 between them, constitute (in conjunction with an undercut opening hereinafter described) a sluice unit, and, in the example illustrated, in each tray 15 there are five series each of four laterally aligned sluice units.

The undercut opening 26 of each sluice unit is a lateral slot formed through the tray bottom 17, which has a strip 27 of polyvinyl chloride or other suitable material secured to its rear edge and extending for a short distance below the level of the tray bottom.

In each of the upgrader trays 15 there is formed through its bottom 17, between the front parts of each pair of sluice units, a rectangular hole, and through each set of corresponding holes of all of the trays 15, a rectangular-section conduit or launder 28 is closely fitted and secured. In each tray 15, the two undercut openings 26 to either side of each launder 28 lead into a pair of chutes 29 under the tray, and leading into that launder.

All of the movable sluice side walls 23 of corresponding sluice units of all of the upgrading trays 15 of the apparatus may be simultaneously adjusted angularly, to vary the angle of convergence of the side walls of the sluice units, thus correspondingly varying the areas of the bottoms of these units, and the width of the outlet opening between the front and lower parts of their side walls, and the Width of undercut opening 26 between the front parts of the side walls of the sluice units. To this end, there extends across each lateral series of sluice units a side shift bar 30, from which there extend downwardly a series of pins 31, each of which engages in a slotted hole in an angle bracket 32 secured to a movable sluice side wall 23, so that lateral slidable movement of the side shift bar will simultaneously move all of the sluice side walls 23 correspondingly. To maintain the movable sluice side walls 23 in contact with the upgrader tray bottom 17, a helical compression spring 33 is provided on each pin 31 between the bar 30 and the bracket 32.

The side shift bars 30 across corresponding series of sluice units of all of the trays 15 are rigidly secured at their ends to a pair of actuating bars 34, which at their upper and lower ends are mounted in laterally slidable manner in channels 35 secured to and extending outwardly of the base channels 10 and the top members 12 of the main frame Each of the actuating bars 34 at one side of the main frame has secured to and extending outwardly from its upper and lower part a bracket 36 with, at its outer end, a pair of parallel apertured lugs 37 between which is pivoted one end of a link 38. The other end of this link is pivoted between a pair of lever arms 39, the two pairs of lever arms 39 extending from the upper and the lower part of a shaft 40 rotatably mounted in bearings 41 on a base channel 10 and an upper member 12 of the main frame. The shaft 40 may be turned, in one direction or the other, to move the actuating bar 34 in parallelism, in one direction or the other, by means of an adjusting screw 42. This screw is mounted in a bracket 43 secured to the said base channel 10, the screw being so held that it is restrained against longitudinal movement, but may be rotated by means of a suitable tool engaging a squared end of the screw. Engaged on the screw is a nut 45 with upper and lower trunnions 46 engaging in recesses 47 formed in the upper and lower arms of a' fork 48 at one end of a double lever 49 secured to and extending from the shaft 40. When the squared end 44 of the screw 42 is turned, the nut 45 is caused to travel along the screw, moving the fork 48 and double lever 49 to turn the shaft 40, thereby, through the lever arms 39, links 38 and brackets 36 moving the actuating arm 34.

So that a head feed of pulp, that is to say, a mixture of water with sand from which mineral sands are to be extracted, may be fed simultaneously to all of the upgrader trays, there is provided a main distributor (not shown) being a tank to which the pulp is fed, and having its lower part divided into equal compartments from which there lead a number of hoses 50, each one of these hoses being connected to an opening leading into a compartment of an upgrading tray distributor 19.

At the front end of the apparatus there is mounted a tailings chute 51, fitted and secured over the front and lower ends of all of the trays 15, and into which tailings from all of the upgrading trays may be gravitationally delivered.

In use, the pulp is delivered at substantially constant and similar rates of flow through all of the hoses 50, and, in each upgrading tray 15, flows through the sluice units of the rear or upper series. In each sluice unit, the pulp spreads over the sluice unit bottom, and it is during its travel over the sluice bottom that it tends to stratify, the denser mineral sands moving towards the bottom, forming a large part of a bottom stratum, the less dense silicon sands forming an upper stratum. At the outlet from the sluice unit, the lower stratum fiows through the undercut opening 26, the upper strata overshooting this opening, spreading out over the bottom of the next sluice unit ahead in line, where the process above described is repeated, and so on until the tailings are discharged, at the front of the tray, into the tailings chute 51.

By adjustment of the angle of convergence of the side walls of the sluice units, optimum results for the particular conditions prevailing, and including rate of head flow and density of the pulp, may be achieved. It is to be noted that stratification of the pulp occurs primarily as the pulp flows over the sluice bottom, and adjustment of the movable side wall of a sluice unit varies the area of the bottom on which this occurs. The convergence of the sluice side walls acts to deepen the flow of the pulp, and of the strata, but excessive constriction is apt to result in turbulence which may break up the stratification which has occurred in the passage of the pulp over the sluice bottom. An undercut opening of which the dimension longitudinally with respect to the sluice is about as narrow as is consistent with free flow of sand therethrough, and with its lateral dimension extended as far as is practical achieves very good results, achievable with the present invention.

The uninterrupted flow of the pulp, with no change of direction apart from some constriction of the flow towards the outlet passage of one sluice unit, and thereafter the spreading with the entry to the next, ensures that the gradual process of stratification of the pulp passing over the sluice bottoms is not disrupted, as is the case with separation plants previously proposed, in which the direction of flow is changed.

When it is desired to maintain a substantially constant pulp density despite the withdrawals of the denser mineral sands at the undercut openings of a longitudinal series of sluice units, this may be assisted by appropriate adjustment of the movable side walls of the sluices.

Apparatus according to the invention may be particularly compact, which is of very considerable practical and economic importance in many sand treatment installations, and in the foregoing and other respects the invention will be found to be very effective in achieving the objects for which it has been devised.

What I claim is:

1. Apparatus for the gravity separation of materials suspended in a liquid, including a main inlet for suspended materials, a tray sloping downward from said main inlet to a tailings outlet, a plurality of series of sluice units on said tray, each series comprising a plurality of generally longitudinally aligned units, each series of said sluice units extending generally parallel to the other series of units, each sluice unit having side walls converging towards the outlet of said unit, means for angularly adjusting at least one of said side walls for varying the angle of convergence of said side walls, said tray being formed with an undercut opening near said outlet, said series of sluice units being positioned so that liquid from said main inlet flows successively through the units of the series to said tailings outlet.

2. The apparatus of claim 1, further including common control means for simultaneously controlling the angular adjustment of said movable side walls.

3. The apparatus of claim 2, wherein said common control means comprises a transversely slidable shift bar.

References Cited UNITED STATES PATENTS 1,105,109 7/1914 Stenger 209-458 FOREIGN PATENTS 521,481 5/ 1940 Great Britain. 694,597 7/ 1940 Germany.

HARRY B. THORNTON, Primary Examiner. FRANK W. LUTTER, TIM R. MILES, Examiners.

L. H. EATHERTON, Assistant Examiner. 

1. APPARATUS FOR THE GRAVITY SEPARATION OF MATERIALS SUSPENDED IN A LIQUID, INCLUDING A MAIN INLET FOR SUSPENDED MATERIALS, A TRAY SLOPING DOWNWARD FROM SAID MAIN INLET TO A TAILINGS OUTLET, A PLURALITY OF SERIES OF SLUICE UNITS ON SAID TRAY, EACH SERIES COMPRISING A PLURALITY OF GENERALLY LONGITUDINALLY ALIGNED UNITS, EACH SERIES OF SAID SLUICE UNITS EXTENDING GENERALLY PARALLEL TO THE OTHER SERIES OF UNITS, EACH SLUICE UNIT HAVING SIDE WALLS CONVERGING TOWARDS THE OUTLET OF SAID UNIT, MEANS FOR ANGULARLY ADJUSTING AT LEAST ONE OF SAID SIDE WALLS FOR VARYING THE ANGLE OF CONVERGENCE OF SAID SIDE WALLS, SAID TRAY BEING FORMED WITH AN UNDERCUT OPENING NEAR SAID OUTLET, SAID SERIES OF SLUICE UNITS BEING POSITIONED SO THAT LIQUID FROM SAID MAIN INLET FLOWS SUCCESSIVELY THROUGH THE UNITS OF THE SERIES TO SAID TAILINGS OUTLET. 